Multiple control



2 Sheets-Sheet April 30, 1929. E. A. BoHLMAN MULTIPLE. CONTROL Filed May 22, 1926 April 30, 1929. E. A. BoHLMAN MULTIPLE CONTROL Filed May 22, 1926 2 Sheets-Sheet Patented Apr. 3o, 1929.

UNITED STATES 1,710,720 PATENT oFFICE.

ERNEST A. BOHLMAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A

MULTIPLE CORPORATION OF ILLINOIS.

CONTROL.

Application led Hay 22, 1926. Serial No. 110,899.

My invention relates to tuning couplers or transformers as are used in wireless telegraph or telephone receiving systems, and resides in a novel method of construction and operation of the same.

A feature of my invention resides in a multiple control arrangement for such de-, vlees.

Another feature of my invention has to d0 with the manner in which the coils are mounted and associated with one another, and the construction and control of the apparatus by which the inductances of the secondaries of the transformers or couplers are varied in steps by means of a single control arrangement.

Another feature of my invention has to do with the manner in which the inductance within the steps is varied by means of a separate single control unit. Y

Another feature of my invention has to do with the manner in which the contact or wiper arms for varying the inductance of the transformers by steps are associated with the control arrangement.

A still further feature of my invent-ion is t-he manner in which the rotary supports within the stator supports are held in position, and the novel means which are pro- 30 vided for leading the terminal ends of rotary coils to terminals which are adapted to receive connections from an external circuit. A further feature of my invention is the novel shielding means which are provided for shielding the transformers and the means for securing the same in position.

A still further feature of my invention is the provision of a novel wiper arrangement in association with a conducting element to provide means for connecting the wiper with an external circuit.

The above features as well as others not specifically pointed out will be more fully described and explained in the following specification and for a more complete understanding of my invention reference may be had to the accompanying drawings in which like references in the several views denote like parts and in which:

Fig. 1 1s a top view of the apparatus'comprising my invention in association with a mounting panel and mountin base.

Fig. 2 is a front view of ig. 1 with the mounting panel removed and the front of the shielding members cut away.

l'contacts associated with the tapped secondaries of the transformers.

Fig. 5 is a sectional view through one of 65 the transformers to illustrate the means for carrying the'terminals of to external terminals.

Fig. 6 is a sectional the rotor winding view along the line view of the wiper illustrating their to which they are Fig. 7 is a fragmentary and arm of a switch unlt association with the shaft secured.

Referring now particularly to Fig. 1 the devices or transformers T, T', T2, 'I3 are each provided with a cylindrical frame or stator tube, 2, 3, 4 and 5 respectively and mounted within.- the stator tubes are rotatable cylindrical frames or rotor tubes 6, 7, 8 and 9 shown in dotted lines in Fig. 1. The stator coils 2, 3, 4 and 5 are mounted upon abase board 10 by brackets and as each of the stator coils is mounted in a similar manner a descri tion of one will suice. A U-shaped bracket 11 is provided with diverging legs 12 and 13 which are provided with tapped orifices 14, and screws 15 which pass through suitable orifices in the stator tube 2 near its peripheral edge have threaded engagement with the tapped orifices 14 in the respective legs 12 and 13 of the bracket 11 to secure the stator tube 2 to the bracket 11, the brackets 11 being in turn secured to the base board 10 by means of screws 11. i

The rotor tubes 6, 7, 8 and 9 are supported on a rod 16 of suitable insulating material such as bakelite and as the rotor elements are supported on the rod 16 in a similar 100 manner a detailed description of one will suffice. The rotor element or tube 6 is provided with a pair of orifices 17 and 18`diametrically opposite which are adapted to receive thersleeve extensions 19 of a pair 105 of bushings 20 secured to the inner circumferential face of the tube 6 b means of' rivets 21. The stator tube 2 1s provided formers T, T', f2 and 24 which extend through the sleeve extensions 19 of the bushings 20. The orifices 22 and 23 in the stator tube 2 and the orifices 24 in the bushings 2() are of the same size and are in alignment, and they are adapted to receive sleeves 25 and 26 which are of a size to receive the supporting rod 16.

The bushings 19 of the rotor tube 6 are provided with tapped orifices 28 which are adapted to receive screws 29 the ends of which pass through orifices 30 in the sleeves 25 and 26 to permit the same to engage the rod 16 to rigidly secure the rotor tube 6 to the rod 16. The sleeve extensions 19 of the bushings 20 protrude through the diametrically opposite orifices 17 and 18 an equal distance so that the distance between the respective ends of the sleeve extensions 19 is approximatel that of the inner diameter of the stator tu e 2, so that the ends of these sleeve extensions 19 when therotor 6 is' positioned in t-he stator tube 2 on the rod 16 engage the inner circumferential face of the stator tube 2 land prevent longitudinal movement of the rotor tube 6 on the supporting rod 16. The rod 16 passes through the respective sleeves 25 and 26 associated with each of the other rotor tubes 7, 8 and 9, and these rotor tubes 7, 8 and 9 are secured to the rod 16 by set screws 29 as described in connection with rotor tube 2 and as the rod 16 is rotated the rotor tubes 6, 7, 8 and 9' which are secured thereto by the set screws 29, are simultaneously rotated. The trans- T3 are of the 90 degree coupler type, so that the rotor tubes 6, 7, 8 and 9 may be rotated 90 degrees or until they are at right angles to the axis of the stator tubes 2, 3, 4 and 5.

A bracket 31 secured to the panel 32 by means of screws 33 which pass through suitable orifices in the panel 32 and extended portions 34 of the bracket 31 and have threaded engagement with nuts 35 which secures the bracket 31 to the panel 32. The bracket 31 extends rearwardly Vfrom the panel 32 between the transformers T and T2 and is provided with an integrally formed portion 36 extending upward at right angles from the bracket 31 which is provided with an orifice through which the rod 16, which supports the rotor tubes 6, 7, 8 and 9 extends. A shaft 37 rotatably supported in integrally formed extended portions 38 and 39 of the bracket 31 has secured to its one end 37 a bevel gear 40 which meshes with a bevel gear 41 secured to the rod 16 b means of a set screw 42. Through the ne ium of the shaft 37 and the bevel gear 40 secured thereto and the bevel ear 41 on the rod 16 simultaneous rotation o the shaft 37 and rod 16 is accomplished.

The other end 37z of the ,shaft 37 extends through an orifice in the panel 32 and has secured to its protruding end a graduated dial D adapted to rotate the shaft 37 and through the medium of the gears 40 and 41 and rod 16 the rotor tubes 6, 7, 8 and 9 are rotated simultaneously. The dial D is provided with suitable graduations and a suitable mark is placed upon the front of the panel 32 to indicate the degree of rotation of the rotor elements. A stop pin 43 secured to the shaft 37 and angular' extensions 44 on the bracket 31 cooperate to prevent excessive rotation of the shaft 37. A coil spring 45 is placed around the shaft 37 with one end resting against the extended portion 39 of the bracket 31 and its other end resting against a collar 46 adapted to be rigidly secured to the shaft 37 by means of a set screw 47. The collar 46 may be slid longitudinally along the shaft 37 to permit the tension or compression of the coilspring 45 to be adjusted and this spring 45 causes the bevel gear 40 on the shaft 37 to be held in mesh with the bevel gear 41 on the rod 16 to prevent any lost motion/between the rod 16 and the shaft 37 and to also provide frictional means to maintain the rotor elements in any adjusted position.

The stator coils SC, SC', SC2 and SC3 are tapped and these taps are led to contacts 48 mounted on panels 49, 50, 51 and 52 and as all of the panels are of similar construction and arrangement the description of one will suiice for a clear explanation of all. The panel 49 associated with the stator coil SC is rectangular" shape and of suitable insulating material such as bakelite and is provided with suitable orifices 53 equally spaced apart which are adapted to receive contacts 48. The contacts 48 are provided with reduced portions 48 which extend through the orifices 53 to which the ta s or leads 54 from the tapped stator coil S are fastened by suitable means such as solder. The contacts 48 are secured in the orifices 53 in the panel 49 in any suitable manner and are arranged in an are of a circle, and a wiper arm 55 is adapted to pass over and engage the contacts 48. The wiper arms 55, 56, 5 and 58 are multiply controlled and adapted to be moved corresponding distances simultaneously, so that the inductances of the transformers T, T', T2 and T3 may be varied by placing a different number of turns ofl wire composing the secondaries of the transformers in circuit. By using a multiple control device the same number of turns will be used on each coil, and thus the most eliicient results with the simplest operation will be obtained and the means for accomplishing this will now be described.

The panel 49v associated with the transformer T is located forward of the same and is secured to the integrally formed angular extensions 59 and 60 of the U-shaped bracket 11 which supports the stator tube 2, by mea-ns of screws 75 which pass through openings in the panel and have threaded engagement with tapped orifices in the extensions 59 and 60. Additional securing means for the panel 49 in the form of a bracket 61 is secured to the same by means of a rivet 62 and is provided with an integrally formed pin member 63 which extends through an `orifice 64 in the stator tube 2 to rigidly secure the uppei` portion of the panel 49 against movement. A bushing 65 provided with a reduced portion 66 is inserted into a suitable orifice 67 in the panel 49 and the reduced ortion 66 in the orifice 67 extends slightly eyond the face of the panel 49 and is upset or spun over to secure the bushing 65 to the panel. The bushing 65 is provided with a central orifice 68 which is adapted to receive a stub shaft 69 which extends through this orifice 68, and the protruding end 69 of the shaft 69 has a portion cut away to form a fiat face 70. A bushing 72 is provided with a circular orifice 73 in its one end and with an orifice 74 in its other end sha ed to conform with the formed end 69 of t e shaft 69 which extends into this shaped orifice 74. The end 69 of the shaft 69 protrudes slightly into the circular orifice 73 of the bushing 72 and this protruding end is staked over to secure this bushing 72 to the shaft end 69.

A shaft 80 extends through an orifice 81 in the front panel 32 into the orifice 73 in the bushing 72, and a set screw 82 having threaded engagement with a suitable tapped orifice in the bu'shing 72 engages this shaft 80 to rigidly secure the same in the bushing 72. The wiper 55 is provided with a dished .portion 55 having an orifice 71 of a size and shape to lit over the formed end 69 of the shaft 69 and this dished portion 55 of the wiper 55 when positioned on the stub shaft 69 rests between the bushing 65 in the panel 49 and the face of an arm 76 secured to the bushing 72. It is readily apparent that as the shaft 80 is turned through the medium of a knob K secured to the end protrudin through the panel` 32 the bush ing 72 and the stub shaft 69 secured to the bushing 72 and the wiper 55 which is supported on the stub shaft 69 are rotated as a whole causing the free end 552 of the wiper 55 to engage successive contacts 48, as it is rotated from left to right and vice versa, though the medium of the shaft 80. The arm 76 secured to the bushing 72 is also rotated and this movement of the arm 76 is for purposes as will presently be described. A bracket 85 secured to the panel 49 by the screws is provided with' an upwardly extended portion provided with an orifice 86 through which the shaft extends and serves as a bearing when the same is rotated and the bushing 65 secured to the panel1 '49 and through which the stub shaft 69 extends serves as a bearing for the shaft 69 when it is rotated through the agency of the shaft 80 as just described. To prevent any overrun of the free end 552 of the wiper 55 as it passes from one contact 48 to the next and also produce a snap action as the wiper 55 passes from one contact 48 to the next` the arm 76 is provided with a downwardly extending portion 76 provided with a plurality of notches 86 in its arcuate shaped edge equal in number to the contacts 48 secured to the panel 49.

The bracket secured to the plate 49 as already described is provided with an orifice 87 which is adapted to receive a ball bearin 88. A leaf spring 89 secured at its one en to the bottom face of the bracket 85 has its free end engaging the ball bearing 88 which rests in the orifice 87 to maintain the ball bearing 88 in engagement with the notches 86 in the arm 76. The ball bearing 88 cooperates with the notches in the extended portion 76 of the arm 76 and as the shaft 80 is rotated the arm 7 6 also rotates causing a tooth 90 formed by two adjacent notches 86 to engage the ball bearing 88 and force it down against the normal tension of the spring 89 and as the arm continues its rotation the ball 88 passes the tooth 90and acts upon the next notch 86 under the influence of the spring 89 so as to give a quick snap action to the wiper 55 and arm 76 as the wiper 55 passes from one contact to the next.

The wipers 56, 57 and 58 associated with the transformers T', T2 and T3 are rotatably supported in a manner similar to that described in connection with the wiper 55 of the transformer T and a description of one will suffice to give a clear understanding of all. The bushing 91 is secured to the panel 50 by staking its protruding end and is provided with a central orifice 92 which receives a stub shaft 93. The stub shaft 93 is provided With a fiat portion 94 and the wiper 56 and arm 77 are provided with orifices shaped to permit them being lslipped on the end 93 of the stub shaft 93, and the end of the stub shaft 93 protruding slightly beyond the face of the arm 77 is staked over to secure the wiper 56 and arm 77 to the stub shaft 93. The wipers 57 and 58 and arms 78 and79 associated with the transformers T2 and T are secured to stub shafts 95 and 96 in a similar manner and the wipers 55, 56, 57 and 58 and arms 76,77, 78 and 79 are rotated simultaneously through means to be presently described.

A link 100 provided with a bifurcated end 101 is associated with the free ends of each of the arms 76, *77` 78 and 79 and straddle the same and are pivotally secured thereto by means of pivot pins 102. Each 'link 100 is provided with an orifice 103 which is adapted to receive a rod 104. Set screws 105 having threaded engagement w1th suitable tapped orifices in the ends of the links 100 engage the rod 104 to rigidly secure the rod 104 to the links 100 to connect the rod 104 with the arms 76, 77, 78 and 79 associated with the wipers 55, 56, 57 and 58. It is readily apparent that `when the shaft 80 is rotated through the agency of the knob K secured to the same, the arm 76 secured to the bushing 72 to which the shaft 80 is secured is rotated, and through the agency of the links 100 which connect the arms 76, 77, 78 and 79 to the connectingI rod 104 the movement of the arm 76 is transmitted to the arms 77, 78 and 79 to simultaneously move them.

The arms 76, 77, 78 and 79 are provided with depending legs 106 which are so spaced apart as to span the wipers 55, 56, 57, and 58. The arm 76 is associated with the stub shaft 69 as before described, and as the arms 7 7, 78 and 79 are secured to the stub shafts 93, 95 and 96 as before described the movement of the arms causes rotation of the stub shafts 93, 95 and 96. The wipers 55, 56, 57 and 58 are secured to the stub shafts and as the stub shafts are rotated by the arms secured thereto the wipers 55, 56, 57 and 58 also move to cause the free ends of the wipers to move from one contact to the next. A pair of stop pins 110 secured to each of the panels 49, 50, 51 and 52 are provided to limit the movement of the wipers from left to right and vice versa, these stops 110 of course being engaged by the iespective edges of the arms 76, 77 78 and Terminals 111 secured to the stator tubes 2, 3, 4, and 5 provide means for securing the terminals of the windings of the stator coils SC and also rovide means for connecting the externa conductors of an electrical circuit. A pair of terminals 112 secured to the stator tubes 2, 3, 4 and 5 by means of screws 113 and nuts 114 are provided with integrally formed parallel spring arms 115 the free ends of which engage respectively the sleeves 25 and 26 which extend into the bushings 20 which support rotor tubes 6, 7, 8 and 9 on the rod 16. The bushings 20 are provided with integrally formed terminals 116 to which the terminal windings of the rotor coil RC are secured. The bushings 20 and sleeves 25 and 26 which extend into the bushings 20 are made of suitable conducting material and contact each other so that the winding terminals of the rotor coil RC are provided with a conducting path including the respective bushings 20 and sleeves 25 and 26 and the arms 115 of the respective terminals 112 secured to the stator tubes. External conductors may be secured to the terminals 112 and thus 'connect the terminal windings of the rotor coils RC to an external circuit.

The wipers are provided with integrally formed dished semicircular portions 553, 56,

57 2 and 582 and are split into sections 120 which are bent down to engage disks 121 which are provided with orifices of a size to fit on the reduced portions of the bushings secured to the panels 49, 50, 51 and 52. The disks 121 are provided with extended portions 122 which are secured to the panels by means of suitable screws and are so formed that when the disks 121 are positioned on the bushings between the face of the panels and the bent sections 120 of the .wipers the same are placed under tension to firmly engage these portions 120 of the wipers to provide rubbing contacts between the disks 553, 562, 572 and 582 and the wipers. The extended portions 122 of the disks 121 are associated with terminals 124 to which external conductors are connected and through the agency of the extensions 122 and the disks 121 which are in contactual engagement with the wiper disks currentis thus carried to the wipers.

The respective transformers T, T', T2 and T3 are shielded and for this purpose I provide containers or shields C, C', C2 and C constructed of suitable metal such as copper and as each one is of similar construction a description of one will suffice. The container C comprises a base 125 secured to the subpanel 10 by means of screws 11 which also secure the brackets 11 to the base board 10. A suitable strip of insulation 126 is placed between the bracket 11 and the base 125 to insulate the bracket 11 from the base 125. The base 125 is provided with u turned ed es 126 and a square shaped tu e or shell 12 is adapted to surround the transformer T and rests on the base 125 inside of the upturned edges 126 of the same. The opposite walls 128 and 129 of the shell 127 are provided with aligned oblong slots 130 through which the rod 16 which supports the rotor elements R, R', R2 and R3 extends. Aligned oblong orifices 131 in the opposite walls 128 and 129 permit the passage of the rod 104 which connects the arms 76, 77 78 and 79 together. A cover 132 with depending edges 133 sets on the shell 127, and with the shell 127 and base 125 as a whole form a container or shield C for the transformer T. A rod 134 secured to sub panel 10 by means of nuts 135 extends upward between the containers C and C and a spring clamping member 136 provided with an orifice through which the rod 134 extends engages the covers 132 of the respective containers or shields C and. C. A nut 137 having threaded engagement with the end of the rod 134 is turned down against the clamping member 136 to place the same under tension to hold the cover and shell in position against movement., The shield C in addition is provided with a slot 140 through which the bracket 85 and shaft 80 extend. The containers or shields C', C2 and Cs are of CII similar construction and the containers C and C3 are also maintained in position by means of a rod 141 and clamping member 142. The shields C, C'. CE and C3 shield the transformers T, T', T2 and T3 as is well understood.

The knob K is rotated to change the inductance of the windings in comparatively coarse steps while the dial D operates to vary the inductance of the secondaries within the steps of inductance between the taps.

The bevelgears which connect the shaft 1G to the shaft 37 have a 2 to 1 ratio s0 that the dial D moves 180 degrees for a 9() degree movement of the rotor elements. By this method a fine adjustmentvof the rotor elements may be made for a coarser adjustment of the dial D.

lVhile I have described a preferred embodiment of my invention I do not however wish to be limited to the exact structure as shown but aim to cover all that comes within the spirit and scope of the appended claims.

Having described my invention what I claim is new and desire" to secure by Letters Patent of the United States is:

1. A device of the character described including a transformer, a stator element and a rotor element for said transformers, a rotatable shaft for supporting the said rotor element, a pair of bushings secured to said rotor element, sleeve members extending through said bushings and said stator element, said shaft extending through said sleeves, and means in said bushings extending through said sleeves and engaging said shaft to rigidly secure said rotor element to said shaft.

2. A device of the character described including a transformer comprising a stator element and a rotor element, a pair of bushings secured to said rotor element, sleeve members extending through said bushings and aligned orifices in said stator element, a shaft extending through said sleeves, and screw means in said bushings' extending through said sleeves and engaging said shaft to rigidly secure said'rotor element to said shaft. i

3. A device of the character described including a transformer comprising a stator element and a rotor element, a pair of bushings diametrically opposite and secured t0 said rotor element, sleeve members extending through said bushings and aligned orifices in said stator element, a shaft extending through said sleeves, set screws in said bushings extending through aligned orifices in said sleeves and engaging said shaft to rigidly secure said rotor element to said shaft, said rotor element being capable of rotating through a predetermined angle within said stator element.

4*. A device of the character described including a transformer comprising a stator element and a rotor element, a pair of bushings diametrically opposite each other and secured to said rotor element, a winding on said rotor element, terminals integrally formed with said bushings adapted to receive the terminal ends of said winding, sleeve members extending through said bushings and aligned orifices in said stator element, a shaft extending through said sleeves, screw means in said bushings extendin through said sleeves and engaging said sha t to rigidly secure said rotor element to said shaft, and terminal means secured to said stator element and enga ing said sleeves to conductively extend sai terminal ends of said rotor winding to said terminal means.

5. A device of the character described including a transformer comprising a stator element and a rotor element, a pair of bushings diameterically opposite each other and secured to said rotor element, a winding on said rotor element, terminals integrally formed with said bushings adapted to receive the terminal ends of said winding, sleeve members extending through said bushings and aligned orifices in said stator element, a shaftextending through said sleeves, set screws in said bushings extending through said sleeves and engaging said shaft to rigidly secure said rotor element to said shaft, terminals secured to said stator element, and extending arms integrally formed with said terminals and engagin said sleeves to conductively connect said terminal ends of said rotor winding with said terminals on said stator element to permit the same to be connected to an external circuit.

6. A device of the character described including a plurality of transformers comprising stator and rotor elements, a pair of bushings for each said rotor elements diametrically opposite each other and secured to said rotor elements, sleeve members extending through said bushings and aligned orifices in said stator elements, a shaft extending through the aligned sleeves, set screws in said bushings extending through orifices in said sleeves and engaging said shaft to ri idly secure said rotor elements to said shat, and means for simultaneously rotating said rotor elements a predetermined degree within said stator elements.

7 A device of the character described including a plurality of transformers comprising stator and rotor elements, a pair of bushings for each of said rotor elements diametrically opposite each other and secured to said rotor elements, sleeve members extending through said bushings and aligned orifices in said stator elements, a shaft etxending through said aligned sleeves, set screws in said bushings extending through orifices in said sleeves and engaging said shaft to rigidly secure said rotor elements to said shaft, a second rotatable shaft mounted at an an le to said first shaft, a gear for each o said shafts for transmitting movement from one of said shafts to the other to simultaneously rotate said rotor elements within said stator elements.

8. A device of the character described, including a plurality of transformers comprising stator and rotor elements, a pair of bushings for each rotor element diametrically .opposite each other and secured to said rotor elements, sleeve members extending through said bushings and ali ned orifices in said stator elements, a sha extending through said aligned sleeves, set screws in said bushings to rigidly secure said rotor elements to said shaft, a second rotatable shaft and a bracket for supporting said second shaft, said second shaft mounted at right angles to said first shaft, a gear for each of said shafts for transmitting movement from said second shaft to said first shaft to simultaneously rotate said rotor elements within said stator elements, and means on said second shaft and said bracket for limiting the rotation ,of said rotor elements.

9. A device of the character described including a supporting member, a coil support connected thereto and having an orifice located near its edge, a contact plate connected to said supporting member, and an angular member having one end secured to said contact plate and its other end entering said orifice in said supporting member for maintainin said contact plate in position relative to sai coil supporting member.

10. A device of the character described including a supporting member, a coil support connected thereto, a contact plate connected to said supporting member, an angular member having one end secured to said contact plate and its other end entering a slot in said coil supporting member for maintaining said contact plate in position relative to said coil supporting member, contacts secured to said contact plate, a wiper secured to said contact plate for cooperation with said contacts, and a second coil support mounted within said first coil support.

11. A device of the character described including a supporting member, a coil support connected thereto, a contact plate connected to said supporting member, a member connecting said contact plate to said coil supportin member, contacts secured to said contact p ate, a wiper secured to said contact plate for cooperation with said contacts, a second coil support mounted within said first coil su port, commutator members connected to saidpsecond coil support adapted for rotation therewith, and contact fingers on said first coil support for cooperation with said commutator members.

12. A device of the character described including a base member, a stationary and a rotor coil support, said rotor coil support being rotat-ably mounted in said stationary coil support, a supporting member secured to said base member and supporting said stationary coil support, a contact panel secured to said supporting member, and additional means comprising an angular member having one end secured to said contact panel and the other end engaging a slot in said coil supporting member for maintaining said contact panel in position relative to said stationary coil support.

13. A device of the character described, including a base member, a plurality of stator coil supports secured thereto, said stator coil supports being mounted in parallel lines and at right angles to said base, rotor coil supports mounted within said stator coil support-s, a shaft extending lengthwise of said base member and through the sides of said stator coil supports, a pair of bushings secured to said rotor coil supports and surrounding' said shaft, and screw means in said bushings adapted to engage said shaft to rotatably' support said rotor coil supports.

14. A device of the character described, including a base member, a plurality of stator coil supports secured thereto, said stator coil supports being mounted in parallel lines and at right angles to said base, rotor coil supports mounted within said stator coil supports, a shaft extending lengthwise of said base member and through the sides of said stator coil supports to rotatably support said rotor coil supports, contact plates associated with and operatively connected t0 the stator coil supports, Contact wipers for each of said contact plates, pivoted control members associated with each of said wipers, and a shaft extending lengthwise of said base secured to said pivoted control members for controlling said contact wipers.

15. A device of the character described, including a base member, a plurality of stator coil supports secured thereto, said stator coil supports being mounted in parallel lines and at right angles to said base, rotor coil supports mounted within said 'stator coil supports, a shaft extending lengthwise of said base member and through the sides of said stator coil supports to rotatably suppolt said rotor coil supports, cont-act plates associated with and operatively connected to said stator coil supports, contact wi ers for each of said contact plates, pivotednr ontrol members associated with each of said wipers, a shaft extending lengthwise of said base secured to said pivoted control members for controlling said contact wipers, a shaft mounted at right angles to the shaft which controls the rotor coil supports for controlling the same, and a second shaft for controlling the movement of said shaft associated with said contact wipers.`

16. A device of the character described including a stator coil support, a rotor coil support adapted to be mounted within said stator coil support, means secured to said rotor coil supports and engaging the inner periphery of said stator coil supports for limiting longitudinal movement of said rotor coil supports, means extending through said first means and orifices in said stator coil supports for rotatably mounting said rotor coil support, and a controlling rod extending through said first means for rotating said rotor coil support.

17. A device of the character described including a stator coil support, a rotor coil support adapted to be mounted within said stator coil support, means secured to said rotor coil support engaging the inner periphery of said rotor coil support for limiting longitudinal movement of said rotor coil support, means extending through said first means and orifices in said stator coil supports for rotatably mounting said rotor coil support, a controlling rod extending through said first means for rotating said rotor coil support, and spring means cooperating with said last means for effecting electrical contact therewith.

18. A device of the character described including a plurality of contact plates, wipers rotatably supported by said contact plates, wiper control members, control de vices pivotally secured to said Wiper control members, and a rod extending through said control devices for effecting operation of said contact wipers.

19. A device of the character described including a plurality of contact plates, wipers rotatably supported by said contact plates, wiper control members, control devices pivotally secured to said wiper control members, a rod extending through said control devices for effecting operation of said contact wipers, and means for movin said rod to simultaneously control sai contact wipers.

20. A device of the character described including a supporting member, a coil support connected thereto, a contact plate connected to said` supporting member, and an angular member having one end secured to said contact plate and its other end entering a slot in said coil support for maintaining said contact plate ,in position relative to said coil supporting member, and a metal housing member for said coil support.

21. A device of the character described including a base member, a stationary and a rotor coil support, said rotor coil support being rotatably mounted in said stationary coil support, a su portin member lsecured to said base mem r an supporting `said stationary coil support, a contact panel secured to said supporting member, .and additional means comprising an angular member having one end secured to said contact panel and its other end entering a slot in said stationary coil support for maintaining said contact panel in position relative to said stationary coil support, and a metal housing member enclosing said stationary coil support and said panel.

22. A device of the character described, including a base member, a plurality of stator coil supports secured thereto, said stator coil supports being mounted in parallel lines and at right angles to said base, rotor coil supports mounted within said stator coil supports, a shaft extending lengthwise of said base member and through the sides of said stator coil supports to rotatably support said coil supports, contact plates associated with and operatively connected to the stator coil supports, contact wipers for each of said contact plates, pivoted control members associated with each of said wipers, and a shaft extending lengthwise of said base secured to said pivoted control members for controlling said contact wipers, and metal housing members for said stator coil supports and contact plates provided with orifices for shafts.

23. A device of the character described including a stator coil support, a rotor coil support adapted to be mounted within said stator coil support, means secured to said rotor coil supports and engaging the inner periphery of said stator coil supports for limiting longitudinal movement of said ro tor coll supports, and means extending through said first means and orifices in said stator coil support for rotatably mounting said rotor coil support, and a metal housing shield enclosing said stator coil supports and provided with an orifice through which said last means extends, said housing shield comprisling a base portion having upturned edges, side member adapted to fit within said upturned edges and a cover portion having edges adapted to surround said side member and means for maintaining said members in position to form a unit structure.

24. A device of the character described, including a base member, a plurality of stator coil supports secured thereto, said stator coil supports being mounted in parallel lines and at right angles to said base, rotor coil supports mounted within said stator coil supports, a shaft extending lengthwise of said base member and through the si es of said stator coil supports to rotatabl support said rotor coil supports, contact plates associated with and operatively connected to said stator coil supports, contact wipers for each of said contact plates, members associated with eac of said wipivoted control ers, a shaft extending lengthwise of said base secured to said pivoted control members for controlling said contact wipers, a shaft mounted at right angles to the shaft which controls the rotor coil supports for controlling the same, and a second shaft for controlling the movement of said shaft associated with said contact Wipers, and metal housing shields enclosing said stator coil supports and said contact plates provided with orifices through which said first shaft and/or said shaft extends.

25. A device of the character described including a supporting member, a coil support connected thereto, a contact plate connected to said supporting member, and an angular member having one of its ends secured to said contact plate and 'its other entering a slot in said coil support for maintaining said contact plate in position relative to said coil su porting member, and a metal housing member for said coil support, and yielding means for holding a cover on said metal housing member.

In testimony whereof I have signed this 25 specification.

ERNEST A. BOHLMAN. 

